Electrical control for multiple



J. H. HOMRIGHOUS 2,434,161

ELECTRICAL CONTROL FOR MULTIPLE HEATING UNITS IN TUBES Jan. 6, 1948.

Filed Aug. 22, 1942 FIGZI FIG 3 FIG I FIG 4 Patented Jan. 6, 1948ELEQTRICAL CONTROL FOR MULTIPLE HEATINGUNITS IN TUBES John H.Homrighous, Oak Park, Ill.

Application August 22, 1942, Serial No. 455,747

11 Claims. 1

This invention relates in general to improvements in electronic tubes,and more particularly to tubes having a plurality of heating units.

One of the main objects of this invention is to provide means forprolonging the useful life of electronic tubes.

Another object of this invention is the provision of switching mechanisminside the evacuated envelope for automatically changing the filament orthe heating units when one is burned out.

Another object of my invention is the provision of means whereby if aheating unit in a vacuum tube be operating at low efficiency it may bereplaced by another heating unit.

Still another object of this invention is the provision of means forvisibly signalling an attendant when the heating unit in an operatingvacuum tube is burned out.

Various types of radio tubes have been devised having several heatingunits that may be separately energized through switching mechanism in anattached accessory. In my invention I provide an evacuated tube or bulb,having multiple heating units with switching mechanism supported in thetube for utilizing the different heating units, the mechanism being heldunder tension or released through the action of a bimetallic springautomatically or manually controlled.

These and other objects and advantages will be apparent from thefollowing detailed description, reference being had to the accompanyingdrawings in which:

Figure 1 is a plan view partially in section of a radio tube withheating unit switching mechanism.

Figure 2 is a top detail View of mechanism taken on lines 2-2 in Figure1.

Figure 3 is a detail view of mechanism taken on line 3-3 in Figure 1.

Figure 4 is a schematic of the circuit.

In the drawing the reference numeral I represents a radio tube brokenaway to show the filament or heating unit switching mechanism on theinside of the evacuated bulb. In the center of this bulb is a hollowstem 4 extending upward from the base and having two ceramic disks 5 andi rotatably mounted near the top of the stem 4. These disks are fastenedtogether by the stabilizing bar i, Figure 2, so that thei will rotatetogether. The disks are limited in their travel by the pin 8 engagingthe elongated slot in the lower rim of the disk 5. The disks 5 and 6,under tension of the spring 9 which is secured to the disk 6 and to theplate ID, are

held in the position shown in Figure 1 by the bimetal stop member I Iengaging the pin I2 in the disk 5. The disk 6 is provided with two pinsI3 and I4 which are connected to the heating units I5 and I6respectively. The other terminals I5 and I6 of the heating units areconnected near the top of the supporting stem 4 to a single conductorextending through the stem 4 to a prong in the base of the tube. Theheating units I5 and I6 may be placed inside of the indirectly heatedcathodes I1 and I8. The bimetal flexing device I I is secured to ceramicplate I0 near the base of the tube and is provided with a coil I9. Theconductors to the coil may extend through the stem 4 to prongs in thebase of the tube or they may be sealed through the side of the tube.Current flowing through the coil produces heat which will flex thebimetal member II outward to disengage the pin I2, whereby the disks 5and 6 will rotate through the action of spring 9.

The brush or wiper 20 is secured to the plate I0 and normally engagesthe pin or contact I3. A conductor may extend from the brush 2!] throughthe stem 4 to a prong in the base of tube.

With reference to Figure 4 showing the circuit arrangement that may beemployed with the radio tube, the relay 2I is connected in series withthe radio tube filament and upon deenergizing responsive to a brokenfilament will cause the lamp 22 to glow.

The operation of the switching mechanism shown in Figures 1, 2 and 3 isas follows, reference being to Figure 4. A source of current supply notshown is supplied over conductors 21 to the heating unit I5, through therelay 2|, contact I3 and brush 20. The relay 2I will now be energizedholding contacts 23 and 24 open. However, should the unit I5 becomebroken or burn out, the relay 2I would release its armature to close acircuit through the lamp 22 at contacts 23, thereby giving a visiblesignal to indicate that a filament has been broken. The release of relay2I will also close a current supply circuit at contacts 24 through theheating coil I9 and switch contacts 25, whereupon the bimetal stopmember I I will be fixed automatically to disengage the pin I2, allowingthe disks 5 and 6 to be rotated through the action of coil spring 9 sothat the brush 20 will contact the pin I4 placing the heating unit orfilament I6 across the current supply circuit.

The switch 25 may be left open. The attendant, upon receiving the signalat 22, may operate the key 26 to effect a change in the heating unit.

The attendant may operate the key 26 at any time to replace a lowefficiency filament with a second filament.

The embodiments of the invention which have been given herein areillustrations of how the various features may be accomplished and of theprinciples involved. It is to be understood that the invention containedherein is capable of embodiment in many otherrforms and adaptations,without departing from the spirit of the invention and the scope of theappended claims.

Having thus described my invention I claim:

1. A radio tube having a plurality of filaments one end of each filamentelectrically ;connected to one terminal of said tube, a brushelectrically connected to another terminal of-said tube-to engageindividual contacts on-the opposite end of each of said filaments, aspring controlled rotatable device for causing said contacts tosuccessively engage said brush, a flexible stop member holding saiddevice under tension ;of said sp in t maintain -1 said brush in ,enasement with one of said filament 1contacts and meansfor flexingsaidstop memberto release the said device-thereby rotatinganother one;of said filament; contacts into engagement with: said brush.

2. An evacuated-radio tube having :a plurality of filaments, a source ofcurrent, a -spr-ing controlled rotatable switch a mechanism -connectingsaid filaments insuccession to the source of ourrent,-a movable holdingdevicemaintain-ing said mechanism under tension of saidcspring toCOnnectone of said filaments to thesource of current, an'electrical releasecoil for saidholding device, and means including said coil for movingsaid deviceto rotate the saidswitch mechanism whereby another one ofsaidfilaments is connected to the source of current.

-3. Anevacuated radio tube having -a;-pl-urality of filaments eachprovided with a contact, a brush, rotatable'mechanism under spring tension for connecting said brush to said contacts in succession, a movableholding devicef-onsaid mechanism to maintain-said brush in engagementwith one of said contacts and means-for moving said device to releasesaid mechanism whereby the said brush engages another-oneof saidcontacts,

4. An evacuated tubehavi-ng apair-of ,filaments each provided with acontact, a brush, rotatable mechanism under spring tension for movingsaid contacts :to engage said brush, a movable holding device for.said'mechanismio maintain said brush in engagement with one of saidcontacts, and -means for automatically moving said-device to rotatesaidmechanism, whereby another one of said contacts is moved into engagementwith said brush.

6. An evacuated radio envelopehaving pair of cathode heaterfilamentsgeach provided with a terminating contact, a brush, switching mechanismin said envelope under spring tension connecting said brush to saidcontacts in succession, a bi-metallic holding device for .said mechanismto maintain the said brush inengagement with .one of said contacts andmeans forfiexing saiddevice to release said mechanism, whereby the saidbrush engagesanother .oneof saidcontacts.

6. In an evacuated radio envelope, ,switching mechanism comprising adiskrotatablysupported in said envelope under spring tension providedwith a pair of contacts-extendingfromithe rim of: the dlsk,;a membermechanically connected .to

said disk provided with a slot, a stationary pin engaging in said slotto limit the rotation of said mechanism, a brush for engaging saidcontacts in succession, a bi-metallic stop member for holding saidmechanism under tension of said sprin to maintain said brush inengagement with one of said contacts, a resistance coil for said member,means including said coil for flexingsaid member out of its holdingposition thereby rotating said mechanism to connect said ,brush withanother one of said contacts.

"'7. An evacuated radio tube having a pair of fila nentseach' providedwith a terminating con- .-tact,.-a brush, a spring actuated switchingmechanism supported in said envelope connecting said brush'to saidcontacts in succession, a bimetallic stopmember hOlding said mechanismunder tension of said spring to maintain said brush in engagement withone of said contacts, a signal device associated with said tube toinforman operator that one of said fila-mentshas beenbr-oken,and-electrical operable -'means to actuate-said-signal device and tocause the said stopmember to flex out of its holding position-to releasesaid mechanism, whereby the saidbrush engages another one of saidcontacts.

'8. An evacuatedradio' envelope, asnap switch mechanism comprising-adiskpivotally supported under-sprin tension in said envelope provided with apair of contacts-extendingfrom the rim of the disk, a membermechanically connected to saiddisk, a stationary pin adapted-toengage-said member to limit the rotation of said mechanism, a brushengaging said contacts in succession, a movable stop --member' holdingsaid mechanism under tension of said spring-to maintain said-brush inengagement with one of said contacts,=and meansfor movin said-stopmember out of its holding position to cause-a snap movement of saidmechanism to connect another one-of said contacts with said brush.

:9. 'Inan article of manufacture, a pair-of electrical 'elementseachprovided witha terminal contact, a spring brush adapted to engagesaid contacts in succession, a snap switch mechanism comprising a diskpivotally mounted under spring tension-connecting the said brush with-afirst one of saidcontacts, a member mechanically connected tosaiddisk,-astationary pin adapted to engage said member to limitrotation of said mechanism, a bi-metallic stop member holdingsaid-mechanismunder-tension of-said spring to maintain said brush inengagement with a second one of said contacts, and means forfiexingsaid-stop-member out of its holding position -to cause a snap-movementof said-mechanism to connect said brush with said first contact.

10. An electrical load element provided with a terminal contact, asource of current supply, aspring brushengaging said contact,'said loadelement, said contact and said brush being connected inseries to saidsource of current'supply; a spring actuated --mechanism adapted toseparate-the said brush fromsaid contact, abimetallic stop memberholding said mechanism under -tension of said spring, and -means forflexing said stop member out of its holding position torelease saidmechanism thereby disengagingsaid brush andsaid contact to disrupturrent flow through said load element.

;11. A radio tubehaving a plurality ,of filaments having one e r 1d .ofeach filament electrically connectedto oneterminal ,of said tube,a-brush electrically. connected .to another 1 termiml of said tube andengaging individual contacts on the opposite end of each of saidfilaments, 8. spring controlled rotatable device for causing saidcontacts to successively engage said brush, a flexible stop memberholding said device under tension of said spring to maintain said brushin engagement with one of said contacts, a si nal member adjacent saidtube for informing an operator that one of said filaments has beendisrupted, means for actuating said signal member following thedisruption of one of said filaments, and means for flexing the said stopmember out of its holding position to release said device to therebyrotate another one of said filament contacts into engagement with saidbrush.

JOHN H. HOMRIGHOUS.

REFERENCES CITED tile of this patent:

Number Number UNITED STATES PATENTS Name Date Voelker July 18, 1882Arnold Apr. 6, 1886 Whitehead Feb. 11, 1896 Tifiany Nov. 30, 1909 QuandtMay 29, 1923 Greger Feb. 21, 1928 Sorell Feb, 9, 1932 Koch Nov. 21, 1933Covington Apr. 13, 1937 Paine Oct. 8, 1940 Schwerin May 13, 1941 DeCastro Apr. 7, 1942 FOREIGN PATENTS Country Date Great Britain Apr. 3,1924 Great Britain Sept. 21, 1925

